Cardiomyocytes lose the ability to divide at the time of birth, and regeneration thereof is difficult. Accordingly, in recent years, considerable attention has been paid to replacement therapies in which cardiomyocytes obtained by induction of differentiation of cells having pluripotency (Patent Literature 1), such as embryonic stem cells (ES cells) or induced pluripotent stem cells (iPS cells), are transplanted into cardiac tissues damaged by myocardial infarction, myocarditis, aging or the like. Many methods for inducing differentiation of such pluripotent stem cells into cardiomyocytes have been reported (Patent Literature 2, Patent Literature 3, Patent Literature 4, and Non Patent Literature 1). However, in order to use cardiomyocytes as cells to be transplanted, it is necessary to increase the purity of the cardiomyocytes by sorting or the like.
At present, many of the reported methods for sorting out cardiomyocytes are methods for sorting cardiomyocytes using a surface marker for cardiomyocytes or myocardial precursor cells (Non Patent Literature 2, Non Patent Literature 3, Patent Literature 4, and Patent Literature 5).